An SAP Consultant

REPORT ztest_program.
*&--------------------------------------------------------------------------*
* Declarations
*&--------------------------------------------------------------------------*
DATA:
      lineType  TYPE REF TO cl_abap_structdescr,
      tableType TYPE REF TO cl_abap_tabledescr,
      key       TYPE abap_keydescr_tab,
      lt_table  TYPE REF TO data.
DATA:
      gv_dref   TYPE REF TO data.
FIELD-SYMBOLS:
     <lt_table>   type ANY TABLE,
     <lt_std_tab> TYPE STANDARD TABLE.
*&--------------------------------------------------------------------------*
* Selection Screen
*&--------------------------------------------------------------------------*
PARAMETERS:
     p_table   TYPE rsrd1-tbma_val.


*&--------------------------------------------------------------------------*
* Start of selection
*&--------------------------------------------------------------------------*
START-OF-SELECTION.

lineType ?= cl_abap_typedescr=>describe_by_name( p_table ).

APPEND 'CARRID' TO key.
APPEND 'CONNID' TO key.

tableType = cl_abap_tabledescr=>create( p_line_type  = lineType
                                        p_table_kind = cl_abap_tabledescr=>tablekind_sorted
                                        p_unique     = abap_true
                                        p_key        = key ).

CREATE DATA lt_table TYPE HANDLE tableType.
ASSIGN lt_table->* TO <lt_table>.

SELECT * FROM (p_table) INTO TABLE <lt_table> UP TO 10 ROWS.

  CREATE DATA gv_dref TYPE TABLE OF (p_table).
  ASSIGN gv_dref->* TO <lt_std_tab>.
<lt_std_tab> = <lt_table>.
CALL FUNCTION 'GUI_DOWNLOAD'
  EXPORTING
    filename              = 'C:\temp\test.txt'
    filetype              = 'ASC'
    WRITE_FIELD_SEPARATOR = 'X'
  TABLES
    data_tab              = <lt_std_tab>.
IF sy-subrc = 0.
  WRITE 'successfully downloaded'.
ENDIF.